Opposition Leader Bill Shorten says Labor must live with its failure to convince Australians of the need for action on climate change, and the party will remain committed to an emissions trading scheme.

And he has fired back at Treasury secretary Martin Parkinson, who on Monday took Labor to task for blocking key budget savings measures while citing "vague notions of fairness".

Speaking at the ANU's Crawford School of Public Policy on Tuesday, Mr Shorten conceded Labor failed to "make the case" to the public on the need for climate action when last in government.

Advertisement

"There's no shrinking from that. But I know there are many leaders in the business community, who spoke against an ETS at the time and now look back with more than a hint of regret at five years of lost certainty and economic opportunity,'' he said.

"Many members of the Greens – and the broader environmental movement - who lament choosing the purity of impotence over the practical benefits of reasonable compromise.

''And many members of the Liberal Party, who rue passing up the chance to move forward, together, on an issue that will define this century."

He welcomed the Palmer United Party's decision to support the retention of the renewable energy target, the $10 billion Clean Energy Finance Corporation and the Climate Change Authority.

On the ETS, Mr Shorten's said Labor's position had not changed.

"It is the position we took to the last election. It is the position we hold now, and it's the position reflected in the amendments Labor has twice moved to the government's repeal bills,'' he said.

''Labor believes climate change is a problem that demands a serious response.''Turning to the budget, Mr Shorten dismissed Dr Parkinson's criticism of Labor's opposition to a string of budget measures.

The opposition has pledged to oppose the reindexation of fuel excise, higher education changes, freezing family tax benefits and the $7 fee for visiting the doctor.

But Mr Shorten was strongly critical of the budget and the "faux language of lifters and leaners"."In four years' time, someone earning a quarter of a million tax will not be paying the temporary income levy ...but if you are on a pension your wage will be decreased,'' he said.

"I think this budget creates inequality and I saw that someone yesterday said that vague notions of fairness didn't do this budget credit. It is not vague if you are under 30 and have no income for six months, that's real.

"It is not vague if you are working class parents weighing up whether to send your kid to university and all of a sudden the cost of a science degree triples."